Electric-arc lamp



(No Model.)

P. H. THOMPSON. ELECTRIC ARC LAMP.

No. 497,558. Patented May 16, 1893.

. WIL

S QM UNITED STATES PATENT OFFICE.

FRANK H. THOMPSON, OF PHILADELPHIA, PENNSYLVANIA.

ELECTRIC-ARC LAM P.

SPECIFICATION forming part of Letters Patent No. 497,558, dated May 16, 1893.

Application filed January 19, 1892. Serial No. 418,567. (No model.)

`To all whom it may concern,.-

Be it known that I, FRANK H. THOMPSON, a citizen of the United States, residing in the city and county ofPhiladelphia, State of Pennsylvania, have invented a new and useful Improvement in Bushings for Electric-Arc Lamps, which improvement is fully set forth in the following specification and accompanying drawings.

My invention consists of a bushing as hereinafter set forth for an electric arc lamp, the same furnishing the contact for the carbon rod, and serving as a guide therefor, and permitting the feed to be gradual, avoiding abruptness in the same.

Figure 1 represents a bottom plan view of a bushing for an electric arc lamp embodying my invention. Fig. 2 represents a central vertical section thereof. Fig. 3 represents a side elevation thereof. Fig. 4 represents a plan view of a modification.

Similar letters of reference indicate corresponding parts in the several gures.

Referring` to the drawings: A designates a bushing which consists of a sleeve B and contact plates O and D on the bottom thereof, said sleeve being screwed or otherwise secured to the base of the lamp or light, and freely encircling the carbon rod. The plate C is adjustably connected with the sleeve by means of a screw E, in said plate, which passes through a slot F into said sleeve, the inner end of the plate being concave and freely contacting with the carbon rod. Vhen the screw is tightened said plate remains stationary in position. The plate D is fitted in a horizontal passage Gin the bottom of the sleeve, and has at its outer end a lip H through which freely passes a screw J, whose threads engage with the sleeve B. interposed between said lip H, or the washer H thereagainst and the head of the screw, is a spring K, whereby by properly rotating the screw, the tension of the spring and the consequent pressure of the plate on the carbon rod may benicely adj usted, the contact of the plates on said rod preserved at all times, and the rod guided in its motion, while the feed is gradual or without abruptness.

In Fig. 4, I show a contact plate in the form of a concave roller, without however, producing different results from those hereinbefore stated.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

l. A bushing for au electric arc lamp consisting of a sleeve having a contact plate with a slot, and a contact plate with body movable in a groove in said sleeve, substantially as described.

2. A bushing for an electric arc lamp consisting of a sleeve having a Contact plate movable in a groove in said sleeve and provided with a lip on its outer end, a screw passing freely through said lip into said sleeve, and a spring bearing against the head of said screw, said parts being combined substantially as described.

3. A bushing for an electric arc lamp having a contact plate supported thereon, a screw connected with said bushing and plate, anda spring` bearing against said screw and plate for adjusting the contact of the latter with the carbon rod, substantially as described.

FRANK I-I. THOMPSON. Witnesses:

JOHN A. WIEDERSHEIM, A. P. JENNINGS. 

